Generator Skills: Choose, Run, Fix, Stay Safe

Types of generators

Look for portable generators certified to UL 2201 or PGMA G300 with a CO shut-off feature (CPSC). Prices: see Home Upgrades.

Most popular generators: budget, mid-grade & premium

We chose these from sales and review evidence as of Oct 10, 2026: retailer review counts, best-seller data, and major review roundups. We picked the most popular model in each price tier. Prices change often, so check before you buy. (Affiliate links may be added later; see our disclosure.)

Also popular: the Honda EU2200i ($1,199 MSRP) is a perennial top pick for quiet, clean power (Bob Vila and Business Insider 2026).

Evidence: Lowe's and Home Depot listings (review counts and prices as shown Oct 10, 2026) · Harbor Freight Predator 3500 · Honda EU2200i · Bob Vila 2026 · Business Insider 2026 · Wirecutter 2026 (top pick: Westinghouse iGen5000DFc, plus two Champion inverters) · Consumer Reports (updated Oct 8, 2026) · Home Depot product listing · Generac 7210 · Grips Intelligence retail data · standby market share (citing GM Insights). Drawings are our own doodles, not product photos. Not an endorsement. Any generator is only as safe as how you use it.

Sizing: running vs. starting watts

Running watts are what a device uses continuously. Motors (fridges, AC compressors) need extra starting watts for a moment when they kick on. Add up the running watts of everything you'll run at once, then add the single biggest extra starting surge. Always check the label on your own device.

Use	Device	Running W	Starting W
	Refrigerator	150–400	800–1,200
	Window AC, 10,000 BTU	900–1,200	1,800–2,400
	Window AC, 5,000 BTU	450–600	900–1,200
	Box/window fans (up to 2)	50–200 each	none
	CPAP with heated humidifier	60–120	none
	Oxygen concentrator (typical; check yours)	≈350	≈600
	Phone/laptop charging	20–100	none
	4 LED bulbs	8–15 each	none
	Internet modem/router	10–20	none

Running: 0 W · Peak (with biggest start): 0 W · Suggested generator (≈20% headroom; hot-weather derating noted below): 0 W

Download the Generator Field Guide (PDF)

Wattages use the high end of the ranges in Champion's wattage chart. The oxygen concentrator figure is a typical value from sizing guides, so confirm with your device's label or supplier. Medical devices should have a battery backup plan too.

Safe setup

• Placement: outdoors on level ground, 20+ ft from the house, exhaust away from openings, never under a carport or porch (CPSC).
• Connecting: plug appliances directly into the generator, or use undamaged, heavy-duty, 3-prong (grounded) outdoor extension cords rated for the load. Thin cords overheat. For longer runs or bigger loads, use a heavier gauge (lower number, e.g., 12 AWG instead of 16). Use GFCI protection per the manual (OSHA grounding fact sheet).
• House wiring: only through a transfer switch or interlock installed by a licensed electrician. When connected to a structure through a transfer switch, the generator must be grounded per code (OSHA).
• Grounding: follow the manufacturer's instructions for your model.
• Phoenix heat: output drops in heat and at altitude. Honda manuals say engine power falls about 3.5% per 1,000 ft of elevation (Honda manual). Generac's GP-series manual cites about 1% per 10°F above 60°F, so at 110°F expect roughly 5% less. Shade the generator from direct sun if you can, but leave plenty of open airflow, and never put it in an enclosure that traps exhaust.
• Noise & theft: chain it to something solid, and be considerate of neighbors at night. Inverter models are much quieter.

Fuel & heat

• Gasoline can start to degrade in as little as 30 days. Add fuel stabilizer to stored gas, and run the engine a couple of minutes so treated fuel reaches the carburetor (Briggs & Stratton). Avoid E15 in small engines.
• Store fuel only in approved, vented containers, never indoors, away from living spaces and ignition sources (OSHA). Phoenix heat speeds evaporation and builds pressure, so keep cans in shade and open them slowly. Store only modest amounts and rotate them.
• Propane stores longer but must be kept outdoors and upright, away from heat.

Moving fuel safely (siphoning)

• Use a hand pump or a self-priming "jiggle" siphon hose, sold at hardware and auto stores, to move fuel between containers or from a mower or generator tank.
• Work outdoors, away from flames, pilot lights, sparks, and running or hot engines. No smoking. Keep a fire extinguisher nearby.
• Fill only approved, labeled fuel containers set on the ground (not in a truck bed or car), and wipe up spills.
• Many modern cars have anti-siphon screens and rollover valves in the filler neck, so a hose often won't reach the tank. That's a safety feature. Don't try to defeat it, and use a different source.
• Take fuel only from vehicles and containers you own or have permission to use.

Gas or diesel? How to tell, and what to do with the wrong one

Skin contact: wear gloves, wash with soap and water, and do the paper test outdoors away from flames. Sources: IRS Publication 510 (dyed diesel), Justrite safety-can color coding, Poison Control.

• Diesel in a gasoline generator (the common case, since most portables are gasoline): it won't vaporize and ignite properly. Expect hard or no starting, smoke, misfires, and fouled spark plugs. Don't keep trying to start it. Drain the tank and carburetor bowl into an approved container, refill with fresh gasoline, and replace the spark plug if it's wet or fouled. If it ran for a while, have a small-engine shop flush it.
• Gasoline in a diesel engine is worse. Gasoline lacks diesel's lubricity and can damage high-pressure fuel pumps and injectors. Do not start it. If it already ran, shut it off and have the fuel system drained and inspected (manufacturer service bulletin via NHTSA).
• Label every can, and never store fuel in drink or food containers.

Step by step (typical portable; follow your manual)

1. Pre-start check: on level ground outside; oil at the full mark; fresh fuel; air filter clean; nothing plugged in; check cords for damage.
2. Start: fuel valve ON, choke ON (cold engine), engine switch ON, then pull the cord smoothly (or press electric start). Ease the choke OFF as it warms.
3. Connect loads one at a time, starting with the largest motor (fridge or AC) and then smaller items. Don't exceed the rated running watts.
4. Shut down: unplug or turn off loads, let it run a minute, engine switch OFF, fuel valve OFF. Let it cool before refueling or covering.

Maintenance schedule (typical; your manual rules)

• Monthly: start it and run it under a light load for 15–20 minutes. Check the oil.
• First oil change after the break-in period in your manual (often about 20–25 hours), then at the manual's interval. Change more often in heat, dust, or heavy loads (Honda).
• Air filter: inspect often in dusty Phoenix conditions (haboobs!). Spark plug: inspect and replace at the manual's interval.
• Storage: stabilized fuel and a short run, or a fully drained carburetor, to prevent gummed jets.

Troubleshooting

Biodiesel and plant oils: the honest version

First, the big caveat: almost every portable generator sold for homes runs on gasoline (or propane). Gasoline engines cannot use biodiesel or vegetable oil. Plant-oil fuels only matter if you have a diesel generator or engine.

What real biodiesel is

Biodiesel is made by transesterification: reacting vegetable oil or animal fat with an alcohol (usually methanol) and a lye catalyst (sodium or potassium hydroxide). The reaction splits the oil into fuel (methyl esters) and a glycerin byproduct (Penn State Extension). At an overview level, Penn State's small-scale guide describes these stages:

1. Oil prep: filter used oil and remove water.
2. Titration: test the oil's free fatty acid content to work out how much catalyst it needs, then run a small test batch before any larger one.
3. Reaction: warm the oil, mix it with a methanol-catalyst solution, and stir.
4. Separation: let the glycerin settle out and drain it off. It must be handled and disposed of properly.
5. Washing and drying: gently wash the fuel to remove soap, catalyst, and methanol, then dry it thoroughly.
6. Quality testing: poorly made fuel can damage engines. Commercial fuel must meet ASTM D6751.

No safe "primitive" shortcut exists. You can't make true biodiesel without an alcohol and a catalyst, and improvised methods mean handling toxic, flammable chemicals without proper equipment. In a real emergency, that's a way to get burned, blinded, or poisoned.

Realistic low-tech alternatives, and their limits

• Straight vegetable oil (SVO) can run some older, mechanically injected diesel engines if it's carefully filtered, dewatered, and heated. It's far thicker than diesel and gels when cool. Usual setups start and stop on diesel and switch to heated oil once warm. The DOE warns that SVO causes carbon buildup and dilutes engine oil over time, even at 1% blends, which shortens engine life. Modern common-rail engines and emissions systems are especially vulnerable (DOE: SVO as a Diesel Fuel?, Penn State/eXtension SVO fact sheet).
• Growing your own oil means low yields. Farm trials found roughly 66–200 gal/acre of sunflower oil, 44–132 gal/acre of canola, and 88–176 gal/acre of soybean oil, plus pressing equipment (Penn State/eXtension). A generator burning about 0.5 gal/hr for 8 hours a day uses about 120 gallons a month, roughly a full year's oil from one acre. Wild desert seeds yield far less.
• Cooking oil you already have is better used as food.
• Where to get biodiesel legitimately: see the Resource Map layer "Fuel & biodiesel resources" for public B20+ stations nationwide (DOE AFDC), production plants (EIA), and farm supply stores. For used cooking oil, ask restaurants with UCO recycling programs. Buy, trade, or get permission.

Which generators can use biodiesel blends?

• B5 (up to 5% biodiesel) meets the normal diesel spec (ASTM D975) and is approved for any diesel engine, including diesel generators. It's often in pump diesel without a label (DOE AFDC).
• B6–B20 must meet ASTM D7467 and works in many diesel engines, but check your engine maker's approval and warranty (AFDC Biodiesel Handling & Use Guide).
• Standby diesel generators: some makers advise against biodiesel blends because fuel sits for months and degrades. Cummins recommends B0 for standby gensets (Cummins white paper).
• Gasoline and propane generators (like the three picks above): no biodiesel, no vegetable oil.

Sources: CPSC Safety Alert, CDC, OSHA 3286, Ready.gov Power Outages, Honda owner's manuals, Briggs & Stratton, and Champion. Always follow your generator's manual. Electrical work on house wiring requires a licensed electrician.

Related: Blackout guide · Home Upgrades